Hey, at least everythings in powers of two (If you start from zero)
Seriously, this is true. Also, what is the vertex limit? I have a feeling I've reached it bfore, and that blender segfaulted rather than complain gracefully.
Increasing limits or making them unlimited, could be non trivial, like replacing arrays with lists that can grow. This also makes the program slower, since it requires dynamic memory allocation instead of static. Its probably the right thing to do in many cases.

I seem to remember that the upper limit for total verts/scene was increased a couple of times. I don't know if those changes were non-trivial or not, but I can only assume that memory allocation for vertex lists etc is dynamic already. I mean, it would be very weird if an empty scene would claim a huge heap of memory and then fill it up as you go...